The available languages are English, French, Spanish, German, Italian, Portuguese, Polish, Russian, Turkish, Japanese, and Chinese. From the app you can sign up for any of the courses available in these languages and start doing all the lessons.
With Busuu it's possible to practice writing, reading, and listening to a language. The vast majority of tests are written, but there are also some where you'll have to use your ears to be able to complete an activity correctly.
Some of the activities you'll find in Busuu include vocabulary and grammar exercises, audio dialogues, and, of course, interactive tests. As you pass the latter, you'll progress to new levels in your language.
Busuu is an excellent language-learning app with a clean, easy-to-use interface and an enormous amount of content.